What this is built on
gradientsmith is an application of ideas that other people worked out first. The list below is the research and the engineering writeups the design leans on, grouped by the part of the platform they inform. Every entry links to the primary source.
Why a verifier instead of a judge
Using a strong model to grade another model is convenient and, for open-ended tasks, sometimes the only option. It is also biased and noisy. These sources measure that noise and show that when a task can be checked by running it, running it is more reliable.
- Judging LLM-as-a-Judge with MT-Bench and Chatbot ArenaZheng, Chiang, Sheng et al., UC Berkeley and LMSYS, 2023
The foundational LLM-as-a-judge study. It reports over 80 percent agreement with human preferences and also documents the judge failure modes: position bias, verbosity bias, and self-enhancement bias.
- Judging the Judges, a Systematic Study of Position Bias in LLM-as-a-JudgeShi, Ma, Liang et al., Dartmouth, 2024
Over 150,000 evaluations across 15 judges. Position bias is systematic rather than random and grows with the quality gap between candidate answers.
- A Statistical Approach to Model EvaluationsEvan Miller, Anthropic, 2024
Argues for reporting eval numbers with error bars, analyzing paired differences between models, and sampling several answers per question to cut scoring variance. The basis for the bootstrap intervals used here.
- LLM-as-a-Judge, Evaluating Natural Language SearchDoorDash Engineering, 2026
An industry account of replacing slow human annotation with a judge that is continuously calibrated against human labels, and the discipline that calibration requires.
- Building Ask DoorDash, Part Three, EvaluationDoorDash Engineering, 2026
A working eval harness for a support agent, built from rubrics, a transcript builder, a repeatable simulator, and a calibrated judge. A good model for the infrastructure around a verifier.
- Execution-based Evaluation for Data Science Code Generation ModelsHuang, Wang, Zhang et al., Microsoft, 2022
Shows that surface metrics like BLEU and CodeBLEU miss functional errors that execution catches. Direct evidence that running the code beats comparing its text.
Reward hacking and reinforcement learning from verifiable rewards
Training against a metric invites the model to game the metric. These sources define that risk and describe the family of methods that reward a model only when an automatic checker confirms the answer.
- Concrete Problems in AI SafetyAmodei, Olah, Steinhardt, Christiano, Schulman, Mané, 2016
The early, careful statement of reward hacking and specification gaming, where an agent satisfies the letter of a reward while missing its intent.
- Sycophancy to Subterfuge, Investigating Reward Tampering in Language ModelsDenison et al., Anthropic, 2024
Shows models trained on gameable rewards generalizing to edit their own reward. Motivation for keeping hidden tests out of the reward and watching for divergence.
- DeepSeekMath, and Group Relative Policy OptimizationShao, Wang, Zhu et al., DeepSeek-AI, 2024
Introduces GRPO, a critic-free policy optimization that estimates advantage from the average reward of a sampled group. The GRPO implemented here follows this.
- DeepSeek-R1, Incentivizing Reasoning via Reinforcement LearningDeepSeek-AI, 2025
Demonstrates that rule-based verifiable rewards alone, without a learned reward model, can drive large reasoning gains. Strong evidence for the verifier-first thesis.
- Tulu 3, Pushing Frontiers in Open Language Model Post-TrainingLambert et al., Allen Institute for AI, 2024
Coins Reinforcement Learning with Verifiable Rewards and open-sources the full recipe over Llama 3.1. The closest published blueprint for a verifier-first post-training stack.
- Let's Verify Step by StepLightman, Kosaraju, Burda et al., OpenAI, 2023
Compares process supervision against outcome supervision and releases PRM800K. Relevant to how much of the verdict signal to expose during training.
Execution-based code evaluation
The benchmarks and methods that established running code against tests, and reporting pass at k, as the standard for measuring code models.
- Evaluating Large Language Models Trained on CodeChen, Tworek, Jun et al., OpenAI, 2021
The Codex and HumanEval paper. Defines the pass at k metric and evaluates by executing generated functions against unit tests in a sandbox.
- Program Synthesis with Large Language ModelsAustin, Odena, Nye et al., Google Research, 2021
Introduces MBPP, a set of short Python problems each with test cases. A model of the task shape used in the seed dataset here.
- SWE-bench, Can Language Models Resolve Real-World GitHub IssuesJimenez, Yang et al., Princeton, 2023
Grades a patch by running the repository's own test suite before and after. Execution-based evaluation at the scale of real projects.
- LiveCodeBench, Holistic and Contamination Free EvaluationJain, Han, Gu et al., UC Berkeley, MIT, Cornell, 2024
Continuously collects fresh problems to avoid training-set contamination, a concern this platform answers with a versioned hidden-test bank.
- BigCodeBench, Benchmarking Code Generation with Diverse Function CallsZhuo, Vu et al., BigCode Project, 2024
Tests harder, library-heavy tasks with rich test cases, a direction the task families here can grow toward.
- SandboxEval, Towards Securing Test Environment for Untrusted CodeRabin, Hostetler, McGregor, Weir, Judd, UL Research Institutes, 2025
On the risks of executing model-written code and what a hardened sandbox needs. Frames where the resource-limited sandbox here sits and where container isolation becomes necessary.
Open model architectures and self-training
The technical reports for the open-weights families a custom harness targets, plus the rejection-sampling and self-training methods that turn a verifier into training data.
- Qwen2.5 Technical ReportQwen Team, Alibaba, 2024
The base and instruct family used here for routing baselines and as a post-training target, with dense models from 0.5B to 72B and long-context support.
- Qwen2.5-Coder Technical ReportQwen Team, Alibaba, 2024
The coder line, the default post-training target here, trained heavily on code with strong results on execution benchmarks.
- The Llama 3 Herd of ModelsLlama Team, Meta AI, 2024
A dense architecture family up to 405B with a detailed account of the post-training recipe, including rejection sampling.
- DeepSeek-V3 Technical ReportDeepSeek-AI, 2024
A large mixture-of-experts model, 671B total parameters with 37B active per token. The reference for the sparse architecture described on the Models page.
- Mixtral of ExpertsMistral AI, 2024
A sparse mixture-of-experts with 8 experts per layer and 2 active per token, a clear worked example of the routing that a harness must account for.
- STaR, Bootstrapping Reasoning With ReasoningZelikman, Wu, Mu, Goodman, Stanford and Google Research, 2022
Keep the samples that reach the right answer, fine-tune on them, repeat. The rejection-sampling loop here is a verifier-gated version of this idea.
- Reinforced Self-Training (ReST) for Language ModelingGulcehre, Paine, Srinivasan et al., Google DeepMind, 2023
Alternates a grow step that samples data with an improve step that fine-tunes on the best samples, a framing for the campaign-then-train loop.
Agent harnesses and why a custom one differs
The default coding harnesses are built to complete one task interactively. An eval harness is built to grade thousands of attempts identically. These describe the former so the contrast is concrete.
- Building Effective AI AgentsAnthropic, 2024
The distinction between fixed workflows and open-ended agents, and when each is appropriate. The eval harness here is a workflow, not an agent.
- Claude Code OverviewAnthropic, 2026
An interactive agent harness for coding in a real repository. Optimized for finishing one task with a human in the loop, not for identical repeated scoring.
- OpenAI Codex CLIOpenAI, 2025
A terminal coding agent with its own sandbox and tool loop. Useful to contrast the agent loop with a deterministic eval loop.
- Unrolling the Codex Agent LoopOpenAI, 2025
A description of the agent loop that these tools run, which is exactly the machinery an eval harness strips out to make scoring reproducible.
- SWE-agent, Agent-Computer Interfaces Enable Automated Software EngineeringYang, Jimenez, Wettig et al., Princeton NLP, 2024
Shows how much the interface between the model and the computer matters. The verifier here is a narrow, fixed interface by design.